mean sun

noun
a theoretical sun that moves along the celestial equator at a constant speed and completes its annual course in the same amount of time the real sun takes at variable speeds
Hypernyms: ↑model, ↑theoretical account, ↑framework

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noun
Etymology: mean (VII)
: a fictitious sun supposed to move uniformly along the celestial equator completing crossings of the vernal equinox at intervals of a tropical year

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Astron.
an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic.

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mean sun noun
An imaginary sun moving uniformly in the equator, its position giving mean time or mean solar time (coinciding with true sun time four times a year)
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Main Entry:mean

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mean sun,
a hypothetical sun in various astronomical calculations that moves uniformly along the celestial equator at the mean speed with which the real sun apparently moves along the ecliptic.

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n. an imaginary sun conceived as moving through the sky throughout the year at a constant speed equal to the mean rate of the real sun, used in calculating mean solar time

Useful english dictionary. 2012.

Look at other dictionaries:

  • Mean sun — Mean Mean, a. [OE. mene, OF. meiien, F. moyen, fr. L. medianus that is in the middle, fr. medius; akin to E. mid. See {Mid}.] 1. Occupying a middle position; middle; being about midway between extremes. [1913 Webster] Being of middle age and a… …   The Collaborative International Dictionary of English

  • mean sun — n. Astron. a hypothetical sun thought of as moving uniformly along the celestial equator at a speed equal to the actual sun s average speed along the ecliptic: hypothesized as a basis for keeping time, because the actual sun does not travel along …   English World dictionary

  • mean sun — mean′ sun′ n. astron. an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic …   From formal English to slang

  • mean sun — An imaginary body which is assumed to travel around the equinoctial at a constant rate, completing one orbit in the same time that the earth takes to complete one orbit around the ecliptic. Because of the elliptical shape of the earth’s orbit,… …   Aviation dictionary

  • mean sun — noun an imaginary sun conceived as moving at a constant speed equal to the mean rate of the real sun, used in calculating solar time …   English new terms dictionary

  • mean sun — /min ˈsʌn/ (say meen sun) noun an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic …   Australian English dictionary

  • mean sun — noun Date: 1765 a fictitious sun used for timekeeping that moves uniformly along the celestial equator and maintains a constant rate of apparent motion equal to the average rate of apparent motion of the real sun …   New Collegiate Dictionary

  • mean sun — Astron. an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic. * * * …   Universalium

  • mean sun — See mean solar time …   Ballentine's law dictionary

  • mean sun time — See mean solar time …   Ballentine's law dictionary

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